Chlorine-fast fluorescent optical



Patented Mar. 9, 1954 CHLORINE-FAST FLUORESCENT OPTICAL BLEACHES Delton William Hein,'Somervi1le, N. J assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine No. Drawing. Application April 29, 1952,

Serial No. 285,061 I This invention relates to new optical bleaching agents for textile fibers and, more specifically,

to new optical bleaching agents of the formula 4 Claims. (Cl. 260-247-1) curred. This was largely due to the lack of ac-'2 ceptable materials. In the last few years, some such materials Have been found and optical in which X represents a radical chosen from the bleaching agents haveappeared on the market" class consisting of Z-hydroxy ethylamino, bis(2- for incorporation in soaps and detergents for" ydr y hyl am and m rp y d M laundering as well as for other similar re lace; represents hydrogen, ammonium, or an alkali ment of blueing. The great majority of the; metal. compounds which have found acceptance are It is well known that cellulosic materials tend derivatives of 4,4-dian inostilbene-2,2' disulfonicto develop an undesirable yellowish cast with age. Unfortunately, it cannot be removed by ordinary simple bleaching or scouring. Development of this yellowness is aggravated, among other reasons, by continued exposure to light,

weathering, and repeated launderings. It is, therefore, particularly troublesome in plastics and textile fabrics that must be subjected to these conditions. a

For many years it has been the practice to attempt to conceal this yellowing by the use of blue pigments or dyes, to neutralize the complementary yellow color of the cellulose. For this purpose,'the use of blue pigments, such as ultra-j marine or. alkali blue, or of fugitive blue dye-. stuffs, has become common practice in paper. manufacture and laundry operations.

While these blue coloring matters are often temporarily effective, they are subject to serious disadvantages. For example, addition of a blue color to a yellow does not produce pure white but, rather, a gray because both colors are absorbing light and reducing the total amount of reflected light. The greater the intensity of the original yellow", the more blueing necessary to hide it, and the darker in cast the resultingfgr'a'y; Further, unless the exact coloring balance is struck, the finished p'roduct'is not even gray, but may actually be blue.

In 1929 P. Krais (Melliands Textilberichte 1929, pp. 468-9) suggested using not a blue color ing matter to absorb yellow light, but aes'culin, a fluorescent substance capable of emitting bluelight. Thus, the yellowing effect, which consists in absorbing the blue light, is truly destroyed by a substance which emits the blue light lost, resulting in a true white instead of a gray, because the total reflected light is at least equal to the incident light.

No widespread acceptance of this proposal ocacid.

The compounds which have appeared on the market have had in common a serious deficiency, namely, a serious instability to the action of sodium hypochlorite. portant failing in view of the almost universal habit of bleaching laundry either during or after the washing, for antiseptic reasons. The, action of the hypochlorite when used during the launder.- ing causes the destruction or alteration of the optical bleaching agent in the soap solution. When the hypochlorite' treatment is carried out after the laundering, the destruction or. altera-' the use of the optical bleaching agent is to make the textile fabric yellower instead of neutralizing the natural yellowing of the fabric, as is intended in the use of fluorescent optical bleachingagentss I The fluorescent optical bleaching agents which contain the -4,4-diaminostilbene-2,2'-disulfonic acid nucleus connected to 1,3,5-triazine: nuclei have formed on'e'of the most im'portant'groups' of these optical bleaching agents in the art. It has been a peculiar property of this class thatit has been especially weak to the action of hypochlorite, although otherwise their properties are highly desirable.

A second disadvantage of many of the optical bleaching agents known to the art has been the instability of their aqueous solutions in the presence i'light. The deterioration of these'agents under such conditions may be due to a stereo- This is obviously an im- Destruction isomeric change in configuration although such theories have never been proven.

I have now found that compounds of the structure soar Am in which X represents a radical chosen from the group consisting of ethanolamino, diethanclamino, and morpholinyl, and M represents hydrogen, ammonium, or an alkali metal, are fluorescent optical bleaching agents of surprising sta* bility to the action of sodium hypochlorite, as well as excellent stability to deterioration in aqueous solution under light. It is not known why this should be so, and I do not wish to be restricted to any theories thereon. Similar compounds in which the anilino groups on the triazine rings are either unsubstituted or are substituted with other groups, such as alkyl or alkoxy, do not show these unusual properties.

The compounds can be prepared by a number of routes. Cyanuric chloride can be reacted with one mole of p-chloraniline, followed by one mole of either ethanolamine, diethanolamine, or morpholine. The resulting disubstituted monochloro triazine can then be reacted with 4,4-diaminostilbene-2,2-disulfonic acid in the ratio of two moles to one. Alternatively, the cyanuric chloride can be reacted first with the diaminostilbene disulfonic acid, followed by successive reaction with the p-chloraniline and the aliphatic amine. Another alternative is to react the cya- CFUNHQENH nuric chloride first with the aliphatic amine, then with the diaminostilbene disulfonic acid and then with the p-chloraniline. Thus, the various amino compounds can be attached to the triazine nuclei in any order.

My invention can be illustrated by the following examples in which the parts are by weight unless otherwise indicated.

Example 1 31... N N OzNa Eighteen and five-tenths parts of 4,4-diaminostilbene-2,2-disulfonic acid was dissolved in 240 parts of water by the addition of sodium carbonate solution until the acid was just neutralized. One hundred sixty parts of acetone was then added, and the solution cooled to C. A second solution of 18.4 parts of cyanuric chloride in parts of acetone was added gradually to the first solution, simultaneously with sufficient sodium carbonate solution to keep the solution approximately neutral during the addition. The mixture was stirred until the reaction was approximately complete. Twelve and eight-tenths parts of p-chloraniline was then added slowly to the mixture, accompanied by the addition of further portions of sodium carbonate to keep the mixture neutral. The mixture was stirred at 55 C. until this condensation was complete, when 15.3 parts of monoethanolamine was added. The acetone was removed by distillation and replaced with an equal volume of water. The mixture was then stirred at the boil to produce a compound having the above formula. Three hundred parts of water was added, and the mixture was further treated after reheating, with 71.5 parts of 10% sodium carbonate solution. On cooling, the product was isolated by filtration as the sodium salt and washed with 10% brine. The yield was excellent. The free sulfonic acid may be prepared from the sodium salt illustrated above by addition of an equivalent amount of a strong mineral acid. The acid can of course, be converted into its ammonium or alkali metal salt by conventional neutralization with the corresponding base.

Example 2 SOJNZI some -o1 Cyanuric chloride was reacted first with 4,4- diaminostilbene-2,2-disulfonic acid and then with p-chloraniline in aqueous acetone, as described in Example 1. The solution was then treated with 26.3 parts of diethanolamine, and the acetone removed by distillation and replaced by Water. The mixture was heated at reflux until the final condensation was complete. The mixture was then diluted with 71.5 parts of 10% sodium carbonate solution. The product was isolated as the sodium salt by filtration from the cooled reaction mixture and washing with 10% brine. The yield was excellent.

Example 3 N N O T N g l N N Cl- OaNa SOaNa C] C CH7 $112 CH2 I OH: H: CH2 Ha 2,671,784 6 The condensation was carried out by the of fluorescence on hypochloriting again amounted method described in Example 1 except that 15 to more than 50 percent. parts of morpholine was substituted for the Exam l8 5 monoethanolamine. The sodium salt was isop lated by filtration, in excellent yields. 5 The produ t f E pl 3 was applied t c t- Emmpze 4 ton muslin in the same manner as described in Example 4 and tested similarly with sodium hy- Five parts of unbleached cotton muslin were pochlorite. It also was found to lose approxiwashed in a launderometer at 130 F. with 125 mately 25 percent of its strength. However, a parts of soap solution containing 0.5 part of 10 compound which difiers from th product of Exsodium oleate and 0.00125 part of the product of ample 3 only in the absence of chlorine from the Example 1. The washed cloth was rinsed at 70 molecule, was much less stable to hypochlorite, F. and split into two equal pieces. One piece was the loss of fluorescence amounting to approxitreated at 90 F. with a solution of sodium hypomately 60 percent. chlorite of approximately 0.5 percent available I claim: chlorine. The other piece was treated with dis- 1. The new fluorescent optical bleaching agents tilled water at the same temperature. A comof the formula NH(NTNH CH=CHNH(NTNH c1- Y soar son I V -Cl parison of the two pieces showed that the hypoin which X is a radical selected from the group chlorited sample had lost approximately perconsisting of 2-hydroxyethylamino, bis(2-hycent of the fluorescence exhibited by the control. droxyethyl) amino, and morpholinyl radicals, and When the product of Example 1 was replaced M is a monovalent cation. by a compound which difiers only in the absence 2. The new fluorescent optical bleaching agent of chlorine from the molecule, the loss of fluoof the formula N N N N C] C 1- S 0 :Na A OaNa rescence on hypochloriting under identical con- 3. The new fluorescent optical bleaching agent ditions amounted to more than percent. of the formula 01 SOaNa some When both chlorines in the product of Exam- 4. The new fluorescent optical bleaching agent pie 1 were replaced by methoxy groups, the loss of the formula NHI INHGCAOHQmI INaOm DELTON WILLIAM I-IEIII.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,376,743 Wendt May 22, 1945 2,618,636 Williams Nov. 18, 1952 FOREIGN PATENTS Number Country Date 624,052 Great Britain May 26, 1949 993,648 France July 25, 1951 OTHER REFERENCES Ser. No. 381,856, Wendt, (A. P. 6.), published May 11, 1943. 

1. THE NEW FLUORESCENT OPTICAL BLEACHING AGENTS OF THE FORMULA 